There are many health risks for obese patients. Cardiovascular disease, diabetes and even some forms of cancer. The immune system can be disrupted when a patient is overweight as well.
Patients who are overweight are more at risk for complications from any illness, but recent research on influenza shows that obese patients are not only at a higher risk for severe complications than non-obese patients, they can also pose a threat to others around them.
A team of researchers from the University of Michigan School of Public Health investigated influenza in obese patients and found that obese patients experience a more extended period of contagion from the flu than patients who are not overweight. Last year's flu season was longer and more severe than any in recent memory, so more information for public health officials on how long some patients are contagious is vital to controlling the spread of influenza.
The study used data from patients at the Health Center Sócrates Flores Vivas in Managua, Nicaragua over the course of three flu seasons, from late 2015 to late 2017. When a patient tested positive for the flu at the clinic, every member of their household was monitored and enrolled in the study. There were two cohorts, patients with obesity and those at a healthy weight.
The researchers took throat swabs every 48 hours and kept a symptom diary for each patient. They monitored "virus shedding" which refers to a patient with an active, contagious flu virus. The adults with obesity shed influenza A virus about 1.5 times as long as adults who were not overweight. The longer a patient is infectious, the more people around them are in danger of catching the flu. Obese patients were contagious for an average of 5.23 days while patients who were not obese only remained contagious for 3.68 days. The same result was not seen in patients who had influenza B. Also, children between 5 and 17 years old who had obesity showed no differences in the duration of shedding either strain of flu.
Study co-author Aubree Gordon, Ph.D., M.P.H., stated in a press release from the Infectious Disease Society, "This is the first real evidence that obesity might impact more than just disease severity, It might directly impact transmission, as well."
Stacey Schultz-Cherry, Ph.D. who directs the Center for Excellence in Influenza Research and Surveillance at St. Jude's wrote an editorial accompanying the study that addressed its implications for public health, writing, "What does this mean for public health? It could mean that, with an increasing prevalence of obesity, the number of episodes of prolonged influenza virus shedding will increase, leading to increased opportunities to infect naïve and high-risk populations." See the clip below for more information.